02 Ranger 4wd 4.0 The problem is, very erratic misfire on #1 cyclinder. Somedays it will not miss at all, somedays it misses all day long. Does not matter if it is cold or hot. I have changed plugs and wires. Run Seafoam thru it, It only misses on #1. I also get low voltage to oxygen sensor. I can be driving it just fine and it will either start to miss or it will be missing and just stop and run just fine. If it was the coil, wouldnt all cyclinders miss? I am at a loss, could I have a bad injector? Do they go bad? Any help/advice would be appreciated.

 

if it was the coil it would miss all the time regardless it wouldnt necessarily be all the cylinders it could be any combonation really, and all car parts wear out over time so ofcourse they can break. try running injector cleaner if the injector was messing up tho it wouldnt run right at all.

 

if it was the coil, it could be intermittent
if it was an injector, it also could be intermittent

when it is missing, listen with a screwdriver, vacuum line, stethoscope etc to the injector and see if it is clicking, if it doesnt sound like the rest of the injectors it could be an injector issue

if you feel comfortable enough, when it is missing, unplug the #1 wire and see if you have spark at the plug.

if you have low voltage from the 02 sensor, that would indicate a lean condition, suggesting that you have a fuel related misfire

how are you checking this voltage? if you are checking voltage to the 02 sensor it is for the heater circuit. o2 sensors create their own voltage based on how much oxygen is in the exhaust stream. the max voltage it will produce is 1 volt in an extreme rich condition

 

while it was running I pulled off plug wire while it was missing, i gots lot of fire there. so either injector is plugged or it has broken wire/type problem. I dropped truck off at garage today. One of those intermittent things I hate, know what I mean?

 

it was the injector, now that I got that fixed(at a garage) my airbag light is flashing. I dont know the code it is flashing yet, I was to mad to look it up.

 

my 96 4.0ohv was doing the same thing! number 1! at the most random times, i did the screw driver test haha, touched number 5 and i can feel it ticking, touched number one barely feel anything, so tomorrow im heading over to NAPA and picking up a new injector and i would assume gaskets? and replace it

 

injectors have o rings but makes sense to do gaskets the rest of the way up.